Probiotic characteristics of Lactobacillus plantarum strains from traditional butter made from camel milk in arid regions (Sahara) of Algeria

Abstract

Lactobacillus plantarum strains previously isolated from the traditional butter made from camel milk (shmen) were evaluated for some probiotic criteria. Among 38 strains investigated for bile resistance, 14 were tolerant to 2% oxgall with survival percentages ranging from 69 to 75%. Out of these, only 4 strains (L. plantarum SH5, SH12, SH24 and SH32) were sufficiently resistant to pH 2.0 for 2 to 6 h incubation periods. Only crude extracts of L. plantarum SH12 and L. plantarum SH24 were inhibitory against Lactococcus lactis B8, the strain used as indicator. The antibacterial activity of crude extracts was completely lost after treatment with α-chymotrypsin and proteinase K. L. plantarum SH12 and SH24 strains were susceptible to penicillin G, oxacillin, vancomycin and clindamycin, but resistant to tetracycline and kanamycin. These strains showed rapid acidification activity (0.921 and 1.075 mmol/l of lactic acid, respectively), a good proteolytic activity (5.45 and 3.49 mg/l tyrosine at 72 h, respectively) and high survival percentage after freeze-drying. None of the strains produced polysaccharides or haemolysin in sheep blood.

Keywords

• antibiotic
• bacteriocin
• butter
• lactic acid bacteria
• lactobacillus plantarum
• probiotics